This invention relates generally to recombinant proteins of Porphyromonas gingivalis, r-RgpA44 and r-Kgp39. The invention also relates to pharmaceutical compositions and associated agents based on these recombinant proteins and derivatives for the detection, prevention and treatment of periodontal disease associated with P. gingivalis. 
Periodontal diseases are bacterial-associated inflammatory diseases of the supporting tissues of the teeth and range from the relatively mild form of gingivitis, the non-specific, reversible inflammation of gingival tissue to the more aggressive forms of periodontitis which are characterised by the destruction of the tooth's supporting structures. Periodontitis is associated with a subgingival infection of a consortium of specific Gram-negative bacteria that leads to the destruction of the periodontium and is a major public health problem. One bacterium that has attracted considerable interest is P. gingivalis as the recovery of this microorganism from adult periodontitis lesions can be up to 50% of the subgingival anaerobically cultivable flora, whereas P. gingivalis is rarely recovered, and then in low numbers, from healthy sites. A proportional increase in the level of P. gingivalis in subgingival plaque has been associated with an increased severity of periodontitis and eradication of the microorganism from the cultivable subgingival microbial population is accompanied by resolution of the disease. The progression of periodontitis lesions in non-human primates has been demonstrated with the subgingival implantation of P. gingivalis. These findings in both animals and humans suggest a major role for P. gingivalis in the development of adult periodontitis.
More recently there has been increasing linkage of priodontal disease and cardiovascular disease and therefore a link between P. gingivalis infection and cardiovascular disease. More information regarding this linkage can be found in Beck, J D et al. Ann Periodontol. 3: 127-141, 1998 and Beck, J. et al. J. Periodontol. 67:1123-37, 1996.
P. gingivalis expresses a range of proteins on its cell surface that are potential candidates for the development of a vaccine or diagnostic. A major group of cell surface proteins expressed by P. gingivalis is a group of proteinases and associated adhesins. One proteinase designated Arg-gingipain has been disclosed previously by Travis et al. (PCT Publication No. WO 95/07286). These investigators also reported a high molecular mass form of Arg-gingipain that is encoded by the gene rgp also disclosed in WO 95/07286. The high molecular mass form of Arg-gingipain consists of the proteinase and several other proteins proposed to be adhesins. Cell-surface complexes of P. gingivalis consisting of Arg- and Lys-specific proteinases and adhesins have also been disclosed by Reynolds et al. (PCT/AU96/00673). Neither of these disclosures provide teaching regarding the utility of a particular adhesin as a recombinant in the protection of P. gingivalis infection.